The present invention generally relates to the field of valves and actuators and more particularly relates to an improved valve stem and handle configuration for quarter-turn valves. The design for the valve employs a xe2x80x9cmodifiedxe2x80x9d square shaped valve stem and a corresponding valve lever. The valve stem and valve lever are keyed so that the valve lever can be fitted to the valve stem only in a manner that will provide a positive visual indication of the valve position, whether open or closed, as the valve stem is turned.
Valve actuators are devices designed for attachment to an industrial valve in order to transmit torque to a valve stem in order to provide for the operation of the valve. Valves typically are actuated by electrical, pneumatic, hydraulic, or manual means or by a combination of these means. Applicant presents a design for a valve stem configuration for quarter-turn valves such as butterfly valves and ball valves that complies with both domestic and international design standards. Applicant""s design also allows for actuators and gear operators that are in compliance with the standards of the International Standards Organization (ISO) to be directly mounted or attached to the valve stem without the need or use of adaptors, brackets, drivers or excessive fastening hardware.
ISO Standard 5211 provides for limitations on the maximum torque that can be transmitted though the mounting flange of a valve and actuator and also places limitations on the dimensions of the driving components for valves and actuators. In the case of valves and actuators having square heads, the ISO standards impose limitations on the dimensions of the head of the valve stem and the actuator output shaft. In addition to the ISO standards, the American Society of Mechanical Engineers and the American National Standards Institute (ASTM/ANSI) publishes and maintain certain standards for quarter-turn valves. For instance ASTM/ANSI B16.34 provides, at Section 6.5.2, the following requirements for the position indication of valve stems:
6.5.2 Position Indication. Valves of the quarter-turn type (e.g., ball, plug, or butterfly) shall have a means to indicate the ball, plug, or disc position. The design shall be such that the components of the indicating means cannot be assembled to falsely indicate the valve open or closed position.
Applicant provides a design for quarter-turn valves having substantially square valve stems that conform to the sizing requirements imposed by the ISO specifications. In addition the valve stem and handle assembly is uniquely configured to provide for a positive indication of the valve position, i.e. whether the valve is open or closed. Because the configuration of the valve stem conforms to the dimensional requirements for substantially square valve stems, the valves of Applicant""s design may be fitted with actuators that conform to the ISO specifications without the use of adaptors or other modifications.
Applicant proposes a new design for quarter-turn valves. The design incorporates a valve stem configured in a xe2x80x9cmodifiedxe2x80x9d square design that conforms to ISO dimensional requirements for square stemmed valves. Applicant""s design also provides means to indicate the valve open or closed position that conforms to the ASME ANSI requirements for position indication of the valve disc or ball. The valve stem of Applicant""s design has four sides of a substantially square configuration. A vertical groove or keyway is placed on one of the sides of the valve stem. The valve includes a detachable turning lever. The turning lever has a substantially square bore that conforms to the valve stem dimensions and a protruding key located in the bore that matches with the keyway of the valve stem. The key is located so that the turning lever may be mounted to the stem in only one desired position. Because the valve stem conforms to ISO dimensional standards, it may be used with ISO compliant actuators without adaptors or intermediate fittings.